SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e795b3efd12adf3ff556131a54848e4fc57fe50d1f109490f66f6ced2cb179e7' 
  AND token = 'MTwJpUgO2o419F4jofZiCHx9IxNsu2LigPy29uFUAWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}